Various printing methods that can be used in rotary printing machines are known. One such printing method is inkjet printing or ink-jet printing. In this method, individual droplets of printing ink are ejected from nozzles in print heads and transferred to a printing material so as to produce a printed image on the printing material. By controlling a plurality of nozzles individually, different printed images can be produced. No set printing forme is used, thus each individual printed product can be designed separately. This allows personalized printed products to be produced and/or, since no printing formes are used, allows small print runs of printed products to be produced at low cost.
The precise alignment of a printed image on the front and back sides of a printing material imprinted on both sides is referred to as register (DIN 16500-2). In multicolor printing, when individual printed images of different colors are combined in precise alignment to form a single image, this is referred to as color registration (DIN 16500-2). In inkjet printing, suitable measures must also be implemented to maintain color registration and/or register.
EP 2 202 081 A1 and JP 2003-063707 A each disclose a printing machine in which the printing machine comprises a first printing unit and a dryer, wherein the first printing has a central cylinder with an integral drive motor dedicated to the first central cylinder, and at least one inkjet print head.
From U.S. Pat. No. 5,566,616 A a printing machine is known which has a rotatable central cylinder, inkjet print heads, a cooling unit and a dryer, which operates either using temperature and air flow or using radiation-induced curing.
From U.S. Pat. No. 6,053,107 A a printing machine is known which has a driven central cylinder and a dryer with a cooling unit.
From U.S. Pat. No. 5,713,138 A a dryer is known which uses radiation to heat a central cylinder from the inside, with a printing material being in contact with the outside of said cylinder, said dryer also having a system for conducting air through an intervening space.
US 2002/166470 A1 and U.S. Pat. No. 5,566,616 each disclose a printing machine which has at least one first printing unit and at least one first dryer, wherein the at least one first printing unit has at least one inkjet print head, at least one first central cylinder and an integral first drive motor, dedicated to the at least one first central cylinder, and wherein the at least one first dryer is embodied as a radiation dryer, and wherein at least one first cooling unit is arranged downstream of the at least one first dryer along a transport path of a printing material through the printing machine.
EP 0 870 613 A1, DE 10 2008 047 027 A1 and EP 1 847 388 A2 each disclose a dryer of a printing machine which is embodied as a radiation dryer and which has at least one ventilating device, which has at least one air infeed line and at least one air removal line.
From US 2011/063389 A1 a printing machine is known, which has at least one first printing unit and at least one first dryer, wherein the at least one first printing unit has at least one inkjet print head and wherein the at least one first dryer has at least one ventilating device, which has at least one air infeed line and at least one air removal line, and wherein the transport path of the printing material through an area of action of the at least one first dryer extends at least 75% in at least one direction having a greater vertical component than an optionally existing horizontal component.